Many industries have a need for metal detectable polymers and articles made therefrom. By way of example, a food, medical or pharmaceutical production line maintains tight audit control of service items that enter the manufacturing facility to assure such items do not accidently enter the production stream as a contaminant that can be fragmented into dangerous shards. Historically, plastics have been precluded from some environments due the inability to locate such articles with product screening X-ray or magnetic detectors. Recently, plastic articles have been developed that are filled with metal particulate or barium sulfate, as detailed in co-pending application Ser. No. 13/372,997 filed Feb. 14, 2012 that are detectable with magnetic or X-ray detectors, yet still process as injection moldable thermoplastics and operate in manner similar to their unfilled conventional counterparts.
By way of example, U.S. Pat. No. 5,897,673 teaches fibers containing fine metallic particles that are cross-linked to the polymeric fiber. While various pure metals are contemplated in the literature, little attention has been paid to the unique problems associated with stainless steel particulate. As many foods and manufactured substances can only be exposed to stainless steel, the lack of stainless steel particle filled fibers precludes the usage of many useful articles from these controlled manufacturing sites. By way of example various wipes, hair covers, suits, aprons and shoe covers and other manufacturing aids or personal protective equipment if made from stainless steel containing fibers could allow better quality control of manufacturing with less stringent audit processes as any such articles lost in a production stream could be detected by X-ray or magnetic anomaly.
Thus, there exists a need for a thermoplastic fiber filled with detectable particulate. There also exists a need for such fibers that process and retain properties of conventional thermoplastic fibers to promote production of various articles from fibers that have the added benefit of being X-ray or magnetically detectable while operating in a manner similar to conventional articles.